Obesity subtypes, related biomarkers & heterogeneity

Abstract

Obesity is a serious medical condition worldwide, which needs new approaches and recognized international consensus in treating diseases leading to morbidity. The aim of this review was to examine heterogeneous links among the various phenotypes of obesity in adults. Proteins and associated genes in each group were analysed to differentiate between biomarkers. A variety of terms for classification and characterization within this pathology are currently in use; however, there is no clear consensus in terminology. The most significant groups reviewed include metabolically healthy obese, metabolically abnormal obese, metabolically abnormal, normal weight and sarcopenic obese. These phenotypes do not define particular genotypes or epigenetic gene regulation, or proteins related to inflammation. There are many other genes linked to obesity, though the value of screening all of those for diagnosis has low predictive results, as there are no significant biomarkers. It is important to establish a consensus in the terminology used and the characteristics attributed to obesity subtypes. The identification of specific molecular biomarkers is also required for better diagnosis in subtypes of obesity.

Keywords: Adipose tissue; HOMA; biomarkers; body fat; genome-wide association studies; heterogeneity; obesity; subtypes.

Figure

Differences between phenotypes of obesity. ^aNormal weight (NW) metabolically healthy and normal visceral adipose tissue (VAT) and normal BMI. ^bMetabolically healthy obese (MHO) individuals have high body mass index (BMI) and healthy metabolic profile, characterized by having excessive body fat, high insulin sensitivity, low VAT/total body fat mass index and low VAT. ^cMetabolically abnormal obese (MAO) individuals present high BMI, are associated with abnormal metabolic profile, high VAT and increased uric acid. ^dSarcopenically obese (SO) are characterized by loss of skeletal muscle mass and function, increases risk of metabolic alterations mainly in older individuals and have high VAT with BMI between 25 and 30 kg/m². ^eMetabolically obese normal weight (MONW) individuals are characterized by high VAT and a normal BMI. Source: Ref. .